Machine gun air cooling means



Dec. 19, 1944. v. A.BROWNING MACHINE GUN AIR COOLING MEANS Filed cm. 29, 1940 a Sheets-Sheet 1 Mimi? lllu Emmi llMMIJHE Dec. 19, 1944. v. A. BROWNING MACHINE GUN AIR COOLING MEANS Filed Oct. 29, 1940 3 Sheets-Sheet 2 g M @v Q Wu: A. BROWN/Na Dec. 19, 1944. v. A. BROWNING 2,365,388v

MACHINE GUN AIR COOLING MEANS Filed Oct. 29, 1940 3 Sheets-Sheet 3 VAL ABROWMN Patented Dec. 19, 1944 MACHINE GUN AIR COOLING MEANS Val A. Browning, Ogden, Utah, assignor to J. M. & M. S. Browning Company, Ogden, Utah, a

corporation of Utah Application October 29, 1940, Serial No. 363,262

6 Claims.

The present invention relates to machine guns and more particularly to an improved air cooled barrel structure for such guns.

The object of the present invention is to provide an air cooled barrel structure for machine guns of the recoil operated type having a readily interchangeable barrel structure such as that shown in the copending application of the same inventor Serial Number 363,263 filed on even date herewith. Heretofore machine guns of the recoil operated type have used water cooling because of the impossibility of readily interchanging the barrel. The water cooling is undesirable because of the necessity of having a water supply, means for circulating the water, and means for preventing leakage of the water into the breech structure. By providing an interchangeable barrel such as that shown in the above-mentioned copending application, it is possible to use the air cooling means of the present invention, thereby eliminating the disadvantages heretofore inherent in the use of water cooling. 7

Although particularly intended for guns of the recoil operated type, the barrel structure here may also be used on guns of the non-recoil operated type. Previously many attempts have been made to satisfactorily air cool such guns, but all such means have had serious disadvantages. In some instances a sleeve of light metal having high heat conductivity has been placed over the barrel; the sleeve being substantially coextensive in length with the barrel and intended to conduct the heat away from same, whereby, due to the greater surface area of the sleeve, rapid radiation of the heat into the surrounding air would occur. The difiiculty with such a structure is that it is impossible in practical manufacture to obtain an intimate heat contact between a sleeve of substantial length and a barrel of substantial length, and, as a result, rapid conduction of heat from the barrel to the sleeve does not occur. Another means has been to make the barrel of substantial mass between the points where greatest heat is generated and then score the mass to provide radiating fins such, for example, as is done in the Hotchkiss gun. This type of structure greatly increased the weight of the gun and, in addition, offered considerable manufacturing difficulrality of relatively short abutting heat radiating members fixed to the barrel and intimately contacting the barrel surface. The advantage of using such heat radiating members is that an intimate contact with the barrel can be obtained over relatively short areas, and as each member makes such intimate contact and is likewise in abutting relation to its adjacent member, the result is in effect a continuous sleeve substantially coextensive with the barrel and having intimate heat contact with it throughout its length.

Another object is to provide the barrel with heat radiating members having radial fins or flanges of considerable size whereby both the mass and. the radiation surfaces are substantially increased. By increasing the mass, greater heat conductivity between the barrel and the air cooling means is obtained, and by increasing the radiation surfaces a greater dispersion of heat into the surrounding atmosphereresults.

Another object is to provide air agitating means associated with and positioned between the fins or flanges of the heat radiating members and so mounted that upon operation of the gun a rapid relative movement between said members and the agitating means is accomplished, thus setting. up violent agitation of the air around the barrel structure.

A still further object is to provide air cooling means which may be manufactured with great ease and facility which permit of ready assembly onto the barrel as well as ready interchangeability of the barrel when the gun is in use and wherein said means do not require any sacrifice in weight to accomplish the results desired.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawings:

Figure 1 discloses a barrel structure incorporating air cooling means showing one embodiment of the invention herein;

Fig. 2 is a sectional view ofFig. 1 to show details of construction;

Fig. 3 is a view taken on the line 33 of Fig. 2;

Fig. 4 is a view of the embodiment shown in Fig. 1, but utilizing different means for supporting the air agitatin means;

Fig. 5 i a view showing another barrel structure having air cooling. means showing another embodiment of the invention herein;

breech casing H], a barrel support II, and a bar- When used on a gun of the recoil operrel I2. ated type, the barrel support II and barrel l2 may be of the type which are readilyremovable from the breech' casing, I ll; the structure .for accomplishing this being shown in the abovementioned copending application to the same inventor.

description of the breech mechanism or the means for readily interchanging barrel structures will be included herein except t o point-out that upon recoil the barrel moves rearwardly each impeller means 20 comprises a relatively circular plate 22 of relatively light thin metal by the barrel support H, whereby upon operation of the gun the radiating fins I9 will move rapidly towards and from the impellers 20 to produce a For purposes of simplicity, no further pumping or blowing action and create violent air currents about the barrel. Although the imapproximately five-eighths of an inch relative to v the receiver I0 and the barrel support ll.- In

the embodiments shown in Figs. 1 to 4 inclusive, the barrel support is in the form of a tubular jacket, the jacket having at'its forward end a piece or plug which slidably accommodates the barrel. The wallof the jacket is provided with slots or openings through which "air may be passed.

- In accordance with the invention herein, air cooling is accomplished by mounting on the barrel 12 (see Figs. 1 11039 a plurality of cylindrical abutting heat radiating members l4 made of any suitable light metal having "a high "heat conductivity, such as an aluminum alloy. Each member i4 comprises an elongated body portion IE provided with a'central borejl'8 through which the barrel passes, and a'radiating fin or flange 19 having a thickness equal to approximately half the length'of the body "portion 1'6 and a diameter approximately equal tothe inside diam-f eterof the barrel support jacket. xWith "the members [4 so constructed, they are secured'onto the barrel of the gunin' any: suitable way, such as by shrinking them thereon, and, when mount ed in the manner shown," a-substantial air space is provided between adjacent radiating "flanges i9, whereby their frontand'rear surfaces 21 will serve to deflect air from 'thi'sspace as "the barrel I moves back and "forward during the firing or the gun.

,It will ben'oted thatwith the heat radiating members so constructed the total length of each is relatively short in comparison to the overall length of-the gun'barrel 12. Because 'ofthis, it is possible to obtain an intimate heat contact between the bore of each member and-the short length of barrel it surrounds-and, inasmuch as the members I4 are in abutting relation thereon,

there is provided in efiect a continuous sleeve coextensive with and intimately contacting the length of barrel subjected to the highest'heat. Because of this intimate contact, the heat is rapidly conducted from the barrel to the mem-.

cludes air agitating means. comprising plates or impellers interposed between the fins of the members 14 and adaptedto cooperate therewith to set up a violent agitation of the air currents upon operation of the gun. To accomplish this,

pellers may besecured in various ways, they are -therear end piece of the barrel support. The

rod .32 has cut therein spaced circumferential grooves 33 for receiving and holding oppositely disposed spring ears v25 formed on eachimpeller 3 2 the grooves 33, whereby when thepartsare assembled the cars will snap into place and hold the impellers ag-ainstlongitudi-nal "movement on the rod.

As previously indicated, when the "impellers -20 are so mounted in a gun of therecoil operated type,' t'he radiating fins l9 will "move relative thereto, resulting in a pumping or blowing 'action-Which will create a rapid circulation of the air the areas between the adjacent fins, thus greatly increasing the air flow in and around the barrelstructure and --the radiation-of heat there from. Moreover, as the impellers or agitating means 20 are of relatively alight material' and fixed -only at one point, they -w-i1l,due to the rapid firing of the gun, setup an extremely fast fluttering action which will further aid in the creationof air flows in and about the *barrel structure.

In order to permit rapid assemblyof the barrel structure, the impeller plates "20 are mounted on the barrel simultaneously with the members 1-4,

and each member has cut therein a -U-shaped' notch '34 with which the slots'ZB of the plates may be aligned, and, when so assembled, the

barrel structure maybe inserted into jacket H. The rod 32; having been secured to the from end piece l5,is then inserted through the 'im} pel-ler slots 26 and notches "34 until its rear end is seated against the rear closed end of the barrel support; With the rod'so seatedythe front end piece I 5 will also be seated in the-outer end or the jacket 1| and maybe secured "in .anysuitable mannenasbythe screws 35;

Referring now to "the" embodiment illustrated in Fig. '4,"it' is'generally similar to that shown in Figs. 1 to 3 except 'for'theconstructi'on :o fthe impeller or agitating means" retaining rodf'33, The rod isis provided at 'bothlien'ds with a c'oimterbore 4'0 in which there'is'seated a spring '42.

The bore 4.0 attire rear :endof the rod'a Lela. scopes onto a pin M secured infthe flange of the rearmost member 14 on thegun barrel, and the bore of the forward end of the rod 38 telescopes onto apin 46 secured in the flange of the reremost member 14 on .the :barrel, thus suspending I the rod between the pins 114 and at. With this construction, upon operation .of the gun the pins, wi'll rmove forwardly and backwardly simultaneously'withthe radiating fins [-9 and will cause compression of the springs 42, thus setting up a rapid simultaneous sliding movement of both the rod 38 and the impellers 20 carried thereby.

The foregoing construction further facilitates assembly in that the pins 44 and 46 may be secured into the members [4, whereupon the rod 38 may be mounted prior to the telescoping of the jacket over the barrel structure.

In the embodiment illustrated in Figs. to '7, the barrel support 49 comprises a pair of laterally spaced, parallel side plates 50 having their forward ends secured to a front end piece 52 and their rear ends secured to rear end piece 53 attachable to the receiver l0. As in the first embodiment, there is provided on the barrel a plurality of abutting members 54, each member being of relatively short length in comparison to the overall length of the barrel. In this embodiment, each member 54 includes a rectangular body portion 56 positioned between side plates 50 and having a bore 58 through which the barrel passes. Here, however, the odd numbered members, counting from the forward end, are provided with laterally extending radiating flanges or fins 60, whereas the even numbered members have vertically extending radiating flanges or fins 66.

Referring initially to the radiating flanges or fins 60, they are of triangular cross section and lie outside of the side plates 50 and are connected to the body portions 56 by throats 62. As indicated, the apex of the triangle is at the top of the flange 60, thus providing opposite air deflecting surfaces 64 inclined toward one another and which, when moved back and forth, deflect the air currents upwardly.

On the other hand, the radiating flanges or fins 06 extend vertically from the body portions 56 and are of trapezoidal cross section and lie between the crossplatcs 50. As seen, the opposite faces of flanges 66 are upwardly and inwardly inclined toward one another and will, upon forward and rearward movement upon operation of the gun, deflect the air currents upwardly. As in the first embodiment, the provision of radiating flanges also substantially increases the mass of the members 54 and provides a larger area for conducting the heat away from the barrel as well as providing larger radiation surfaces.

In order to further agitate the air currents in and around the segments, there is also provided between the vertical radiating flanges 66 a plurality of baffles or plates of relatively thin metal mounted in vertical slots 12 cut in the inner walls of the side plates 50. With this arrangement, upon operation of the gun the members 54 will move relative to the baffles Hi to produce a pumping or blowing action, causing a rapid agitation of the air in and about the vertical radiating flanges 66. Simultaneously, the lateral radiating flanges 60 deflect the air upwardly along the side plates 50 carrying away the heat of the side plates and creating an updraft tending to draw the heated air from between the side plates.

The construction shown in Figs. 5 to '7 is also readily assembled as the members 54 may also be initially secured onto the barrel as by shrinking them thereon. Thereafter the side plates 50 may be located in the grooves formed between the lateral flanges 60 and the body portions 56, and the plates 50 then secured to the end pieces 52 and 53. Following this, the bailles Ill may be readily slid into position between the side plates 50.

From the foregoing it will be seen that in all of the embodiments of the invention illustrated herein substantially the entire area of the barrel which is subjected to high heat is enclosed within a sleeve consisting of a plurality of members, each member having a relatively short length in comparison to the overall length of the barrel. This short length assures an intimate contact with the short length of the barrel which passes therethrough, resulting in rapid heat conductivity therebetween. In addition, each member further carries radiating means which greatly increase both the mass of the member and the radiating surfaces thereof for rapid dissemination of heat. Likewise, in each embodiment there is provided means to cause a rapid agitation or violation of the air currents upon the firing of the gun, due to the relative movement between the radiating flanges fixed to the barrel and the impellers or baflles located therebetween.

It is also evident that the air cooling means could be used on guns of the non-recoil operated type. In like manner, the agitating means could be used in conjunction with other types of air cooling means and also on non-recoil operated types of guns. In such guns, because of the manner in which the agitating means are suspended, vibration from the gun would be sufiicient to set up rapid movement thereof, whereby they will tend to displace the air and cause rapid circulation in and around the barrel structure.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. A machine gun barrel structure comprising a barrel, a plurality of longitudinally spaced apart heat radiating flanges fixed to the barrel and in intimate heat contact therewith, a plurality of air agitating plates interposed between said flanges, and means supporting said plates for movement relative to one another and relative to said flanges whereby when the gun is fired said plates are set in rapid motion to cause deflection of the air from the spaces between said flanges.

2. A machine gun barrel structure comprising a barrel, a plurality of longitudinally spaced apart heat radiating flanges fixed to the barrel and in intimate heat contact therewith, a plurality of air agitating plates interposed between said flanges, a member extending longitudinally of said barrel and with respect to which the barrel is movable when the gun is fired, and mean resiliently connecting said plates to said member.

3. A machine gun barrel structure comprising a barrel, a plurality of heat radiating flanges spaced apart longitudinally of the barrel and en circling the same and in intimate heat contact therewith, a rod spaced from the barrel and extending longitudinally thereof, means supporting the rod, and a plurality of air agitating plates in- 4v terposed between said flanges and fiexibly'connectedto said rod.

4. A machine gun barrel structure comprising.

a barrel, a plurality of heat radiating flanges spaced apart longitudinally of the barrel andg ncircling the same and in intimate heat contact therewith, .a rod spaced from the barrel and extending longitudinally thereof, said rod having spaced apart circumferential grooves, means supporting the rod, and a plurality of air agitating plates surrounding the barrel and interposed between said flanges, each of said plates having a pair of opposed spring fingers engaging inwa re spective groove of said rod.

5. A machine gun barrel structure comprising L5 a barrel support, a barrel supported thereby for longitudinalimovement relative thereto, a plurality of heat radiating flanges spaced apart longitudinally of the barrel, and encircling the same and :in. intimate heat contact therewitlna rod carried bysaid support and extending 'lonand connected to said'rcd.

.6. A machine gun barrel structure comprising a barrel, a plurality of heat radiating flanges spaced apart longitudinally of the barrel and encircling the same and in intimate heat contact therewith, a rod extending longitudinally of said barrel, means carried by the front and rear radiating flanges Supporting said rod for longitudinal movement, compression springs interposed between said supporting means and said rod, and a plurality of agitating plates interposed between said flanges andconnected to said rod.

; VAL (A. BROWNING. 

